1. Field of the Invention.
The present invention relates to microcircuitry test equipment and, more particularly, to probe test connections to chips after tape or bumped tape has been attached.
2. Description of the Related Art.
Many processes exist for the production of microcircuit test probes. For example, probes have been designed which are disposed over a recess, and the testing circuit is brought into contact by bending the probes into the recess. Probes have also been produced by bending metallic elements, as disclosed, for example, in U.S. Pat. No. 3,702,439 to McGahey et al. In U.S. Pat. No. 3,832,632, Ardezzone has suggested a flexible coating over a probe head. Probes have also been embedded in flexible structures by processes such as those suggested in U.S. Pat. Nos. 3,810,016 to Chayka et al and 3,835,381 to Garretson et al.
In the disclosed methods and structures, at least some bending is performed on the probe or a related metal structure, either during manufacture or during operation. Bending leads to fatigue and breakage, especially in the case of microcircuits, since the element to be bent is very fine. In addition, probes meant to be bent are relatively flat and are thus relatively weak.
Another method for the production of microcircuit probes includes welding of an aligned probe to a preformed base which has, integral in it, a flexible area. As disclosed by Best et al in IBM Technical Disclosure Bulletin, Vol. 15, No. 11 (April, 1973), the mandrel for the base is then removed to produce a flexible testing unit. The process requires microwelding or brazing.
In U.S. Pat. No. 4,649,338 to Dugan, a process is disclosed which improves on previous processes requiring microwelding or brazing by directly forming the probes in the proper angular relationship to the remainder of the unit. The disclosed method produces new and improved fine-line probes for connection to very fine circuits.
U.S. Pat. No. 4,125,310 discloses the fabrication of printed circuit contact terminations having a plurality of copper buttons covered with a very thin layer of gold plating. A plurality of these contacts, mounted on a wafer in opposed juxtaposition to a corresponding pattern of adjacent circuit contacts, is brought together with the other circuit terminations and pressure is applied sufficient to force-flow the gold layer to develop a gas-tight seal between the opposed surfaces. Such an arrangement lends itself to separation and re-sealing of the contact arrays, thereby providing a special purpose circuit connector.
Further improvements in processes in which probes are formed directly should have the desirable characteristics of (1) enabling reproduction of the probe section of a tester for microcircuits without great difficulty; (2) producing a tester that has relatively rigid probes which are manufactured independent of each other; (3) producing probes that are not easily bendable toward or away from each other; and (4) producing probes which do not break easily.